PCC Natural Markets, a co-op with eight stores in the Seattle area, notified all its brokers, vendors and manufacturers on Feb. 11 that they must trace and disclose all of the ingredients in the products they carry. In addition, they must provide signed statements that any products they sell to PCC are free of ingredients from cloned animals or their offspring.

PCC CEO Tracy Wolpert said the co-op is concerned that federal laws don't require disclosure or identification of certain ingredients, including some oils and spices, along with the sources of colors and flavors, in food products. She also noted that food manufacturers can reformulate their products without notice to retailers or consumers.

As a result, Wolpert said in a statement, it's "incumbent on leaders in the natural foods industry to step forward and provide [the traceability] our consumers want."

PCC Grocery Merchandiser Stephanie Steiner said requiring suppliers to identify and document all their product ingredients and sources will be a "challenge," but added: "The fact remains that doing so is possible."

Trader Joe's announced Feb. 11 that it would stop selling single-ingredient items from China, including garlic, frozen organic spinach, ginger and edamame, by April 1. The specialty foods retailer, which operates 285 stores in 23 states, believes the foods are safe, but "we will continue to source products from other regions until our customers feel as confident as we do about the quality and safety of Chinese products," spokeswoman Alison Mochizuki said in a statement.

Trader Joe's will still carry processed foods made with Chinese ingredients.

According to a USA Today/Gallup poll last summer, 83 percent of U.S. consumers are concerned about food from China, while only 39 percent are concerned about food grown in the U.S.

China is a leading exporter of garlic, apple juice and seafood, and is the sixth largest foreign supplier of agricultural products to the U.S., according to a report last July by Caroline Smith de Waal, director of food safety for the Center for Science in the Public Interest.

Wegmans Food Markets, a 70-store chain in New York, New Jersey, Pennsylvania, Virginia and Maryland, will reportedly require its seafood suppliers to test for mercury levels in tuna, although a spokeswoman refused to comment to NFM. According to Wegmans' Web site, the retailer has a "long history" of testing its swordfish for mercury.